E.E. "Doc" Smith's Lensman series comes to mind. FTL? Well, remove inertia from the object. Then move as quickly as particle drag will let you (in space!). The result is sweet streamlined space ships (the fastest being shaped like a modern-day missile).

The Vacuum of space isn't perfect. In fact, there's a lot of gas out there. That, after all, is what the sun feeds on. It's easily possible to produce a better vacuum in the lab. So, if your space ship is going to go very very fast, there may be a need for streamlining at some point. Depends how fast you're ship is going, and how dense the gases are that you're passing through.

through nebulae this is certainly true, but as you approach relitavistic velocities, it doesn't matter how streamlined or not your ship is, you better have some damn good radiation shielding because at that speed particles act like waves, and those waves can mess you up. well.... i don't think that's the whole reason, but in addition to you having alot more particles acting like waves going through, you also act like a wave kind of, and while i'm not entirely sure what this means for your interactions with stationary particles, i'm sure it's both interesting and dangerous. obviously any macro- results of this are purely hypothetical, seeing as we have a hard time getting more than a couple atoms going near C at any given time.